101 



disappearing, and Lhe more or less anastomosing and irregular 

 knobs now and then divided in a very irregular manner, or bearing 

 irregular processes. PL 18, fig. 12 — 15, which represents British 

 specimens. It is nearly always much attacked by animals, new 

 formations are formed so as to cover these as well as other extra- 

 neous objects, the edges often being free, or the overlapping flaps 

 nearly in contact with each other bend downwards and form a 

 deepening over the overlapping object, which, however, also may 

 be a knob or a short branch, or not closed at the summit, that 

 sometimes may be more or less compressed or wavy, and in all 

 assuming peculiar forms, most of which probably are raised in its 

 struggle for existence, as specimens not much attacked by animals 

 more or less approach f. depressa also in habit- 

 Besides the above mentioned specimen from the west coast I 

 have seen another from the same locality (Sulen in Sogn), that 

 most probably belongs to f. Harveyi, but it is sterile and the lower 

 . or older parts nearly destroyed, the upper and younger ones co- 

 hering tubes of Serpula, shells and other objects. 



A British specimen from Chapman's Porl. Dorset, referred by 

 Batters to the same form, rather reminds one of certain forms 

 of L. polymorphum and especially f. tuberculoid in habit. The 

 ■crust is about 2 mm. thick, with rather densely crowded and in 

 part anastomosing knobs up to 7 mm. high and 5 mm. in dia- 

 meter, but more or less irregular in shape, and here and there 

 with some wart-like piocesses. It on the other hand seems to 

 be nearly related to f. Harveyi and not unlikely belonging to 

 this, but it is sterile and cannot, therefore, be determined with 

 -certainty. 



As to the structure the species appears often to be rather 

 varying. In the form depressa I frequently found the cells of the 

 upper thickening layers to be about 10 — 12 [i long and 5 — 6 jx thick 

 on a radial section, and pretty uniform, but especially in f. Har- 

 veyi the named cells sometimes are of about the same size some- 

 times much larger even in one and the same specimen. Here I 

 found them up to 18 p. long and 9 /■>■ broad, nearly always elongated, 

 with rather thin walls. Occasionally the cell-rows are in vertical 



